Slinkey, waiting alone in the signal-box, had tried the lever again and again by means of which the points were opened that would turn the train on to the branch, and had satisfied himself that everything was in working order. Both the distance and the home signal-lamps showed the white light, so that the train would speed on unsuspectingly with unslackened pace. Slinkey at the best of times was a nervous timid creature--a man who walked ever in trembling dread of the hand which he knew would some day be laid suddenly on his shoulder--but now that he was left alone, now that he had no longer Lardy Bill's audacious bulldog courage to help to animate his own, his craven heart sank lower and lower, and he would have given a year of his life to be well out of the adventure into which he had allowed himself to be seduced.
The low deep hum of the oncoming train grew palpably on the ear. Instinctively, Slinkey's hand closed on lever No. 3, while his heart began to beat a sort of devil's tattoo after a fashion that was far from comfortable. Suddenly he gave a great start, and for a moment or more the tattoo came to a dead stop. He had heard a sound that he remembered full well: it was the noise caused by the explosion of a fog-signal. At the same instant the engine began to whistle its shrillest. Then came the explosion of a second signal, and then the whistle ceased as suddenly as it began. And now he could faintly hear the soft rhythmical pulsing of the engine, as it might be that of some antediluvian monster till it was scant of breath; and Slinkey knew that the train had slackened speed and was feeling its way forward slowly and cautiously. What could be the matter? What could have happened? By whom and with what intent had fog-signals been placed on the line on a night so clear and beautiful?
Such were a few of the queries that flitted through Slinkey's puzzled brain. And now not even the faintest pulsing of the engine could be heard. Could it be possible that treachery was at work, and that the driver had been warned and the train brought to a stand? Slinkey ran lightly down the steps and, kneeling, laid an ear once more to the rails. Not a sound came to him; the train and those in charge of it might have vanished into space, so unbroken was the silence. He got on his feet again, his tongue and throat as dry and constricted as those of a man who had been athirst for days. Instinctively his eyes turned to the tree to which the captured signalman had been bound; but he was too far away to be able to discern whether the man was still there. With a heart that misgave him, he hurried up to the tree, only to find that the prisoner had escaped. The cords were there, but the man was gone. Evidently, treachery was at work somewhere. Would not the wisest thing he could do be to decamp while he had a chance of doing so? He was asking himself this question but had not answered it, when up came Crofton, Lardy Bill, and one of the other men, at double-quick time. They, too, had heard the fog-signals, and had been as much at a loss to account for them as Slinkey had been. But when the latter told them that by some mysterious means their prisoner had contrived to escape, it was evident both to Crofton and Lardy that their carefully planned scheme had met with some dire mishap. They had been betrayed, but by whom? A traitor had been at work, but who was he? Each of them stared suspiciously at his fellows.